bevy/crates
Carter Anderson 1bb751cb8d Plugins own their settings. Rework PluginGroup trait. (#6336)
# Objective

Fixes #5884 #2879
Alternative to #2988 #5885 #2886

"Immutable" Plugin settings are currently represented as normal ECS resources, which are read as part of plugin init. This presents a number of problems:

1. If a user inserts the plugin settings resource after the plugin is initialized, it will be silently ignored (and use the defaults instead)
2. Users can modify the plugin settings resource after the plugin has been initialized. This creates a false sense of control over settings that can no longer be changed.

(1) and (2) are especially problematic and confusing for the `WindowDescriptor` resource, but this is a general problem.

## Solution

Immutable Plugin settings now live on each Plugin struct (ex: `WindowPlugin`). PluginGroups have been reworked to support overriding plugin values. This also removes the need for the `add_plugins_with` api, as the `add_plugins` api can use the builder pattern directly. Settings that can be used at runtime continue to be represented as ECS resources.

Plugins are now configured like this:

```rust
app.add_plugin(AssetPlugin {
  watch_for_changes: true,
  ..default()
})
```

PluginGroups are now configured like this:

```rust
app.add_plugins(DefaultPlugins
  .set(AssetPlugin {
    watch_for_changes: true,
    ..default()
  })
)
```

This is an alternative to #2988, which is similar. But I personally prefer this solution for a couple of reasons:
* ~~#2988 doesn't solve (1)~~ #2988 does solve (1) and will panic in that case. I was wrong!
* This PR directly ties plugin settings to Plugin types in a 1:1 relationship, rather than a loose "setup resource" <-> plugin coupling (where the setup resource is consumed by the first plugin that uses it).
* I'm not a huge fan of overloading the ECS resource concept and implementation for something that has very different use cases and constraints.

## Changelog

- PluginGroups can now be configured directly using the builder pattern. Individual plugin values can be overridden by using `plugin_group.set(SomePlugin {})`, which enables overriding default plugin values.  
- `WindowDescriptor` plugin settings have been moved to `WindowPlugin` and `AssetServerSettings` have been moved to `AssetPlugin`
- `app.add_plugins_with` has been replaced by using `add_plugins` with the builder pattern.

## Migration Guide

The `WindowDescriptor` settings have been moved from a resource to `WindowPlugin::window`:

```rust
// Old (Bevy 0.8)
app
  .insert_resource(WindowDescriptor {
    width: 400.0,
    ..default()
  })
  .add_plugins(DefaultPlugins)

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(WindowPlugin {
  window: WindowDescriptor {
    width: 400.0,
    ..default()
  },
  ..default()
}))
```


The `AssetServerSettings` resource has been removed in favor of direct `AssetPlugin` configuration:

```rust
// Old (Bevy 0.8)
app
  .insert_resource(AssetServerSettings {
    watch_for_changes: true,
    ..default()
  })
  .add_plugins(DefaultPlugins)

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.set(AssetPlugin {
  watch_for_changes: true,
  ..default()
}))
```

`add_plugins_with` has been replaced by `add_plugins` in combination with the builder pattern:

```rust
// Old (Bevy 0.8)
app.add_plugins_with(DefaultPlugins, |group| group.disable::<AssetPlugin>());

// New (Bevy 0.9)
app.add_plugins(DefaultPlugins.build().disable::<AssetPlugin>());
```
2022-10-24 21:20:33 +00:00
..
bevy_animation Rename play to start and add new play method that won't overwrite the existing animation if it's already playing (#6350) 2022-10-24 21:01:09 +00:00
bevy_app Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_asset Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_audio Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_core tick local executor (#6121) 2022-10-24 13:46:40 +00:00
bevy_core_pipeline Accept Bundles for insert and remove. Deprecate insert/remove_bundle (#6039) 2022-09-21 21:47:53 +00:00
bevy_derive Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_diagnostic Add Exponential Moving Average into diagnostics (#4992) 2022-10-24 13:46:37 +00:00
bevy_dylib Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_dynamic_plugin Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_ecs Implement IntoIterator for ECS wrapper types. (#5096) 2022-10-24 21:01:08 +00:00
bevy_ecs_compile_fail_tests Fix tests breaking when new WorldQuery impls are added (#6317) 2022-10-21 11:15:06 +00:00
bevy_encase_derive Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_gilrs feat: add GamepadInfo, expose gamepad names (#6342) 2022-10-24 14:33:50 +00:00
bevy_gltf Spawn now takes a Bundle (#6054) 2022-09-23 19:55:54 +00:00
bevy_hierarchy Add set_parent and remove_parent to EntityCommands (#6189) 2022-10-24 14:33:49 +00:00
bevy_input feat: add GamepadInfo, expose gamepad names (#6342) 2022-10-24 14:33:50 +00:00
bevy_internal Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_log Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_macro_utils Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_math Add Camera::viewport_to_world (#6126) 2022-10-05 22:16:26 +00:00
bevy_mikktspace Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_pbr Implement IntoIterator for ECS wrapper types. (#5096) 2022-10-24 21:01:08 +00:00
bevy_ptr Bump Version after Release (#5576) 2022-08-05 02:03:05 +00:00
bevy_reflect bevy_reflect: Fix DynamicScene not respecting component registrations during serialization (#6288) 2022-10-24 14:53:12 +00:00
bevy_render Optimize rendering slow-down at high entity counts (#5509) 2022-10-24 19:24:49 +00:00
bevy_scene bevy_scene: Replace root list with struct (#6354) 2022-10-24 21:01:11 +00:00
bevy_sprite Add globals struct to mesh2d (#6222) 2022-10-10 19:23:43 +00:00
bevy_tasks tick local executor (#6121) 2022-10-24 13:46:40 +00:00
bevy_text Fixes incorrect glyph positioning for text2d (#6273) 2022-10-18 13:28:34 +00:00
bevy_time Re-add local bool has_received_time in time_system (#6357) 2022-10-24 20:42:13 +00:00
bevy_transform Fix documentation for looking_at/look_at (#4696) 2022-10-12 20:18:20 +00:00
bevy_ui Fix clipping in UI (#6351) 2022-10-24 14:33:51 +00:00
bevy_utils Remove Sync bound from Local (#5483) 2022-09-12 04:15:55 +00:00
bevy_window Plugins own their settings. Rework PluginGroup trait. (#6336) 2022-10-24 21:20:33 +00:00
bevy_winit Update wgpu to 0.14.0, naga to 0.10.0, winit to 0.27.4, raw-window-handle to 0.5.0, ndk to 0.7 (#6218) 2022-10-19 17:40:23 +00:00